# US 12,184,083 B2 · Synchronous rectifier for use in a wireless power transfer system and method for synchronous rectification in wireless power transfer

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- Number: US 12,184,083 B2
- Document ID: US12184083B2
- Status: Granted
- Kind: B2
- Application number: 18/069,423
- Filed: 2022-12-21
- Published: 2023-04-20
- Granted: 2024-12-31
- Earliest claimed: 2020-09-11
- Assignees: Solace Power Inc.
- Applicants: Solace Power Inc.
- Inventors: Chris Rouse; Amir Tahavorgar
- Web page: https://patentgrep.com/patent/US12184083B2

## CPC

- H02J 50/12: of the resonant type
- H02M 1/007: {Plural converter units in cascade (push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826)}
- H02M 1/08: Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
- H02M 7/217: using semiconductor devices only
- Y02B 70/10: Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

A rectifier for use in a receiver of a wireless power transfer system for receiving wireless power transferred for a transmitter of the wireless power transfer system. The rectifier comprises a field effect transistor (FET) comprising: a source terminal electrically connected to ground; a drain terminal electrically connected to a receive element of the receiver. The receive element is for extracting power from the transmitter of the wireless power transfer system. The FET further comprises a gate terminal electrically connected to the receive element. The gate terminal is driven by a gate signal in phase with an input signal received at the receive element.

## Claims

### Claim 1

A rectifier for use in a receiver of a wireless power transfer system, the rectifier for receiving wireless power transferred from a transmitter of the wireless power transfer system, the rectifier comprising a field effect transistor (FET) comprising:
a source terminal electrically connected to ground;
a drain terminal electrically connected to a receive element of the receiver, the receive element for extracting power from the transmitter of the wireless power transfer system; and
a gate terminal electrically connected to the receive element, the gate terminal driven by a gate driver outputting a gate signal in phase with an input signal received at the receive element, the rectifier further comprising,
a trigger circuit electrically connected to the receive element and the gate driver, the trigger circuit outputting a trigger signal for operating the gate driver, wherein the trigger circuit comprises,
a sampling circuit for sampling the input signal; and
a delay line for delaying output of the sampling circuit such that the gate signal is synchronized with the input signal received at the receive element.

### Claim 2 (depends on 1)

The rectifier of claim 1, wherein the trigger signal comprises a pulse signal.

### Claim 3 (depends on 1)

The rectifier of claim 1, wherein the sampling circuit is a voltage divider.

### Claim 4 (depends on 1)

The rectifier of claim 1, wherein the trigger circuit comprises:
a comparator for generating a clock signal by comparing a delayed signal output by the delay line to a direct current (DC) voltage level.

### Claim 5 (depends on 1)

The rectifier of claim 1, wherein the trigger circuit comprises:
a resistor-capacitor (RC) delay circuit for delaying output of the sampling circuit such that the gate signal is synchronized with the input signal received at the receive element.

### Claim 6 (depends on 5)

The rectifier of claim 5, wherein the RC delay circuit comprises at least one resistor electrically connected to at least one capacitor.

### Claim 7 (depends on 5)

The rectifier of claim 5, wherein the trigger circuit comprises:
a comparator for generating a clock signal by comparing a delayed signal output by the RC delay circuit to a DC voltage level.

### Claim 8 (depends on 1)

The rectifier of claim 1, further comprising at least one:
the gate driver for receiving the trigger signal and producing the gate signal for input into the gate terminal to control operation of the rectifier; and
an input stage for at least one of: optimizing load impedance, ensuring current input to the drain terminal is approximately sinusoidal, and reducing harmonics.

### Claim 9 (depends on 1)

The rectifier of claim 1, further comprising:
a converter for converting a signal for powering the trigger circuit.

### Claim 10 (depends on 1)

The rectifier of claim 1, wherein the rectifier is a load-independent class E synchronous rectifier.

### Claim 11 (depends on 10)

The rectifier of claim 10, wherein zero-voltage switching (ZVS) operation of the rectifier is retained from a no load condition to a full load condition.

### Claim 12 (depends on 10)

The rectifier of claim 10, wherein a switch-node waveform of the rectifier does not vary with load.

### Claim 13 (depends on 1)

The receiver for extracting power from the transmitter of the wireless power transfer system, the receiver comprising:
the receive element for receiving wireless power transferred from the transmitter; and
the rectifier of claim 1, the rectifier electrically connected to the receive element.

### Claim 14 (depends on 13)

The receiver of claim 13, wherein the receive element is for extracting power via resonant and/or non-resonant electric or magnetic field coupling.

### Claim 15 (depends on 1)

The wireless power transfer system for transmitting power via magnetic or electric field coupling, the wireless power transfer system comprising:
the transmitter comprising a transmit element for generating a magnetic or electric field;
the receiver comprising:
the receive element for extracting power from the magnetic or electric field via magnetic or electric field coupling, respectively; and
the rectifier of claim 1, the rectifier electrically connected to the receive element.

### Claim 16 (depends on 15)

The wireless power transfer system of claim 15, wherein an operating frequency of the system is 13.56 MHz or 27.12 MHz.

### Claim 17 (depends on 1)

The rectifier of claim 1, wherein the delay line comprises a lumped element delay line circuit.

### Claim 18 (depends on 17)

The rectifier of claim 17, wherein the lumped element delay line circuit comprises a three-stage lumped-element transmission line circuit or a four-stage lumped-element transmission line circuit.

### Claim 19

A method of rectifying an input signal received at a receive element of a receiver of a wireless power transfer system, the receiver comprising a rectifier comprising a field effect transistor (FET) comprising:
a source terminal electrically connected to ground;
a drain terminal electrically connected to the receive element; and
a gate terminal electrically connected to the receive element, the method comprising:
driving the gate terminal by a gate driver outputting a gate signal in phase with the input signal received at the receive element;
driving the gate driver for generating the gate signal;
receiving the input signal at a trigger circuit;
operating the gate driver via a trigger signal output by the trigger circuit;
sampling the input signal via a sampling circuit; and
delaying output of the sampling circuit such that the gate signal is synchronized with the input signal received at the receive element.

### Claim 20

A method of receiving wireless power, the method comprising:
extracting power from a magnetic or electric field generated by a transmit element of a transmitter of a wireless power transfer system by a receive element of a receiver of the wireless power transfer system; and
rectifying the extracted power with a field effect transistor (FET), the FET controlled via a gate signal in phase with a signal of the extracted power, the gate signal output by a gate driver operated by a trigger signal output by a trigger circuit electrically connected to the receive element, the gate signal synchronized with an input signal received by the receive element via a delay line delaying output of a sampling circuit sampling the input signal.